1. Field of the Invention
This invention relates generally to vehicle systems and networks, such as railway systems including trains travelling in a track or rail network, and in particular to a locomotive-to-wayside device communication system and method for use in implementing a communications architecture in a vehicle network, preferably a vehicle network of multiple trains operating in a railroad track network.
2. Description of Related Art
Vehicle systems and networks exist throughout the world, and, at any point in time, a multitude of vehicles, such as cars, trucks, buses, trains, and/or the like, are travelling throughout the system and network. With specific reference to trains travelling in a railroad track network, the locomotives of such trains may be equipped with or operated using train control, communication, and management systems (e.g., positive train control systems), such as the I-ETMS® of Wabtec Corp. In order to effectively manage all of the trains, information and data must be communicated and distributed over the network between the trains, i.e., the locomotives, a central control system, e.g., central dispatch, and various wayside devices, e.g., wayside interface units (WIUs), radios, track communication devices, and other equipment positioned throughout the track network.
As is currently implemented in existing train control, communication, and management systems, the wayside devices, i.e., the data radios of such devices, are configured to either passively respond to an inquiry from the train management computer on the locomotive, or actively and continually transmit data to the train management computer.
When implemented in the above-mentioned passive system, the wayside device is in a “sleep” state awaiting an interrogation signal from the communication system of the train management computer on the locomotive. Based upon the location or position of the train with respect to the wayside device, the locomotive will transmit such an interrogation signal, which “wakes up” the wayside device, such that it enters an active state. In this active state, and based upon the nature and content of the interrogation signal, the wayside device will transmit data associated with the track, the environment, a configurable device (e.g., a switch), the device itself, or other specified information. Once the data is transmitted to the train management computer, the wayside device again enters the “sleep” or passive mode until another interrogation signal is received. One example of a train control system operating in this “passive” implementation is shown and described in U.S. Pat. No. 6,996,461. In the “active” implementation, the wayside device continually transmits the data to the network, regardless of whether or not a train is in the area.
The “passive” implementation is normally used in areas where a continual power source is not available. Accordingly, the wayside device is provided with one or more batteries to supply power to the device, and facilitate the data collection and transmission functions. The “active” implementation can be used in areas that have a permanent power source available, such that the wayside device is hardwired to a power source or system. If the battery-powered wayside devices were to continually transmit, the batteries would drain at a rapid rate, and require replacement or require large infrastructure (wind generators, solar panels, and/or the like) or some other replenishable power source to keep up with the power demands.
Accordingly, there is a need in the art for more effective and efficient communication systems for distributing data and information over a large network, such as a train network. There is also a need in the art for a locomotive-to-wayside device communication system and method that can be used in areas or environments where a permanent power source is not available, or such use not desirable.